Automobile heater



Nov. 25, 1941. H, J, DE N. MccoLLuM 2,263,999

AUTOMOBILE HEATER Filed Feb. 17, 1940 Patented Nov. 25, '.1941

UNITED s-TATESPATENT oFFIcE Application February 17, 1940, Serial No. 319,555

Claims.

My invention relates generally to automobile heaters, and more particularly to improved electrical circuits and apparatus for controlling the operation of automobile heaters of the internal combustion type.

This application is a continuation in part of my copending application Serial No. 61,213, filed January 28, 1936, which has matured into Patent No. 2,191,173, issued February 20, 1940.

It is an object of my invention to provide an improved means for rendering an automobile heater of the internal combustion type inoperative whenever the temperature of parts of the heater become excessively high due to some abi normal condition.

A further object is to provide yan improved control circuit for automobile' heaters of the internal combustion type, in which a solenoidactuated switch is provided to disconnect the electrical portions of the heater from the 'automobile battery whenever the heater becomes abnormally hot.

A further object is to provide an improved controlling circuit and apparatus for automobile heaters of the internal combustion type which will be effective to render the heaterl inoperative whenever it attains an abnormally high temperature, and to prevent re-energization of the electrical portions of the heater when the temperature falls to a normal value.

Other objects will appear from the following description, reference being had to the accompanying drawing, in which:

Figure 1 is a fragmentary'sectional view of an. internal combustion type automobile heater showing the important operating parts thereof;

and, n

Figure 2 is a schematic wiring diagram showing the improved electrical control circuits.

As shown in Fig. 1, the heater comprises a combustion chamber l0 to which a mixture of fuel and air-is supplied by a carburetlng device l2, the latter being connected to a suitable source of liquid fuel by a conduit I4. The mixture of fuel and air; provided by the carbureting device `l2 flows through a tube I6 and implnges upon a baille plate i8 which has suitable openings formed along the periphery thereof. The combustible mixturein the combustion chamber I@ isignited by means of an igniter 2B which is preferably in the form of a coil of high resistcombustion discharged through the passageways in the reigniter 22 ow through a circuitouspassageway formed'in. a radiator` casting 24 which is preferably made of an alloy consisting of approximately 95% aluminum and 5% silicon. The casting 24 is surrounded by a shell 26 preferably made of copper and which has a plunected to a valve 30 cooperating with a, seat 32 formed at the inlet end of a compensator Vnozzle 34 which has alVenturi-shaped passageway extending therethrough. I

When'the Valve 32 is opened byy pulling outwardly on the control button 28, suction is applied to the outlet end of the tortuous passageway through the radiator casting 24 through a conduit 36 which is connected tothe intake manifold of the automobile engine, or other suction producing means, and which communicates with the passageway through the compensator nozzle 34. The heating unit is preferably mounted in the passenger compartment of the vehicle, being supported by a plurality of `brackets 38 which are bolted to the dash or fire Wall 40 of the vehicle which separates the engine compartment from the passenger compartment thereof.

Air from the passenger compartment is 'circulated downwardly over the radiator by means of a fan 4l driven by an electric motor 42. Means may be provided to admit additional air to make the mixture supplied to the combustion chamber more lean when the heater attains its normal operating temperature, such means being illustrated as a bimetal thermostatic valve 44 which, when cool, closes the""end'of a passageway 46. and when heated, opens to admit atmospheric air to make more lean the mixture flowing to the combustion chamber.

ance wire, such as nichrome wire, and flows from Means are provided to extinguish the flame` in the heater should the fan motor 42 fail to operate normally, or should the heater become excessively hot for any other accidental reason. This means comprises a tube 48 threaded in the combustion chamber casting 'and carrying a valve seat fitting` 50 at its outer end. A valve 52 is cooperable with the seat formed in the end of f the fitting 50 and is normally held in engagement therewith by a U-shaped strip 54 of thermostatic bimetal. The bi-metal strip 54 and a bracket 56, which may befof sheet metal, are secured to the valve tting 50 by a nut 58. When the valve- 52 is open, air is admitted through the tube 45 in suicient quantities to dilute and cool the combustible mixture passing into the combustion chamber, thereby preventing it from burning. Under the influence `oi? excessive heat in the heater, the bi-metal 54 tends to straighten and the free end thereof moves outwardly. The valve 52 and bi-xnetal 54 are constructed and arranged so that there is lost motion between them, and the free end of the bi-metal 54v will move outwardly a short distance before it moves the valve 52 to admit air to the combustion chamber.

y The bracket 56 supports a contact 50 which is connected to one terminal of the solenoid 5 5 and is suitably insulated from the bracket 55. A contact 62, engageable with the contact 60, is carried by the free end of the bi-metal strip 54. The contacts 60 and 62 are positioned and arranged so that the co'ntact 52 engages the contact 60 as the bi-metal strip 54 raises the valve 52 from its seat to put out'the burner flame. The bimetal strip is, of course, grounded through its connection with the metallic parts of the heater through the valve fitting 50 and tube 48, although, if desired, an additional grounding connection may be supplied.

Without theprovision of the contacts 65, 52 and the circuit associated therewith, to be described hereinafter, the bimetal strip 54will be effective to raise the valve 52 from its seat whenever the temperature. of the strip is raised materially above the temperature it attains during normal operation of the heater. If, for example, the motor 42 should failgto operate, the air, instead of being forced downwardly past the radiator, would rise by convection and heat the bimetal strip 54 sufllciently to cause it to open the valve. The opening of the valve would result in the admission of atmospheric airto the l combustion chamber in sufficient quantity to render the mixture incombustible. After such occurrence, the heater 4would of course gradually cool off, and when it had cooled to a sufciently low temperature, the igniter 20 would again be energized and the heater again commence op- Vas the case may be, approaches its normal operating temperature, the thermostatic switch will open and thus disconnect the ignite; 2l from the battery 54.

should the heater overheat, due to failure of the fan motor 42 or any other reason, the bimetal strip will ex outwardlyand carry the conclosed. Such. return of the bimetal strip 54 to its normal shape will not, however, result in reenergization of the igniter circuit or the fan motor circuit because the solenoid 66 is not provided with a return spring, and the plunger `thereof will therefore remain in the position with the result that an excessive load would be y placed upon the battery of the automobile because of the frequency with which the igniter 20 would be energized under such conditions.

To obviate such intermittent operation of the heater, I have provided the control circuit shown in Fig.V 2, wherein the contacts B0, 82 are adapted to complete a circuit including the source of electrical energy 54 (usually lthe storage battery of the automobile) -and the winding of-a solenoid 66. 'I'he plunger ofthe solenoid 55 is connected to operate a switch 55 which is preferably of the toggle type and which is adapted to-con nect the motor 42 with the battery 54. The switch 68 also controls the supply of current to a thermostatic switch 10, which, upon closure, energizes the igniter 20. switch 10 is attached to the combustion chamber casting or radiator of the heater so as to be rather rapidly affected by the change in temperature resultantias the heater begins to operate normally. As soon, as the temperature of 'the radiator or the combustion chamber casting.

shown in Fig. 2, and the switch 68 will remainv open. If the defect in the system which caused overheating was of a transitory charactenthe heater will again commence operating in a nor- Ymal manner as soon as the operator closes the switch 68. If, however, the defect was of a permanent character, the operator of the vehicle will realize this fact after a few attempts to cause the heater to start operating normally by closing the switch 58.

l 'I'he control circuit thus provides a convenient means for apprizing the operator of the vehicle that there is a defect in the heater. At thesame, time, the control circuit does not continue to consume energy from the battery, since, as soon as the. heater cools toa normal temperature, the contacts 50, 62 will separate and deenergize the solenoid 85, and the igniter circuit and the fan motor circuit will of course remain open due to the open switch 68.

While I have shown and described a particular embodiment of my invention, it will be apparent to those skilled in the art that numerous variations and modifications thereof may be made without departing from the underlying principles of the invention. I therefore desire, by the following claims, to include within the scope of Ai'ny invention such .similar and modified forms by which substantially the results of the invention may be obtained by substantially the same or equivalent means. 4

I claim :l y

1. In a heater for automotive vehicles, the

combination of a radiator located in the passenger compartment of the vehicle, a fan for circulating air from said compartment past said 615, ated by said thermostatic means and located to prevent the circulation of heating fluidv through said radiator when the temperature surrounding said thermostatic means exceeds a predeterminedA maximum, a switchoperated by said thermo- The thermostatic -static'means and closed thereby when the flow of heating fluid through said radiator is prevented by Isaid valve, and electromagnetic means,

combination of a radiator, a fan for circulating air from the passenger compartment of the ve-y hicle past said radiator, an electric motor for operating said fan, a source of electric current, a-

manually operable switch for connecting said source to said motor, thermostatic means responsive to the temperature of said radiator, a valve operated by said thermostatic means to prevent the iiow of heating uid through said 'radiator when the temperature thereof reaches a predetermined maxlmumvalue, a switch operated by combustion type having a combustion chamber, an electrically operated igniter, a heat radiator,

and-an velectric motor carrying a fan for circulating air past said radiator,'a temperature respon# sive element, a valve operated by said element to prevent the combustion of fuel in said combussaid thermostatic means and closed thereby when heating uid is prevented from owing through said radiator, and electromagnetic means controlled by said last named switch to open said manually operable switch when said thermally operable switch is closed. A

. 3. In a vacuum operated automobile heater of the internal combustion type having a combustion chamber operating under'vacuum an electrically operated igniter, a heat radiator, `and electrically operated means for circulating air past said radiator, a thermostatic element respon*- sive to the temperature of said air, a valve connecting said combustion chamber with the atmosphere and operated by said thermally responsive means and opened therebywhen the temperature thereof exceeds a predetermined maximum value to prevent fuel from burning in said combustionchamber, and acontrol circuit operated by said thermostatic element to prevent energzation of said electrical igniter and said electrically operated meanswhen said valve is open.

4. In an automobile heater of the internal tion chamber when said temperature responsive element attains a predetermined high temperaf ture, and a control circuit' operated "by sai-d element to Aprevent energization of saidelectrical igniter and to deenergize saidmotor whenever said .combustion is prevented.

5. In a vacuum operated automobile heater of the internal combustion type 'havinga combustion chamber operating under vacuum, an electrically operated ignitenassociated with said combustion chamber,` a 4heat exchange device, a

temperature responsive switch receiving heat from said heat exchange device, a s ource of electrical energy, a` circuit connecting said source,

said temperature responsive switch, andsaidigniter in series, avmanually operable switch in said circuit, means re'sponsive to a'n abnormal temperature'condition oi" said lheater for admitting air to saidcombustion chamber to prevent the combustion of fuel therein, a contact-switch operated by said means, a solenoid. having a plunger connected to said manually operable switch and eiective upon its energization to open said manually operated switch', and a circuit cori-A necting saidcontact switch and the winding of said solenoid in series with said source of electrical energy. 

